Feat: add stale clean step

[yyzxw]

Description of your changes

copilot:all

Fixes #

I have:

• Read and followed KubeVela's contribution process.
• Related Docs updated properly. In a new feature or configuration option, an update to the documentation is necessary.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR if necessary.

How has this code been tested

Special notes for your reviewer

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (62efa9c) 66.33% compared to head (c845b63) 66.34%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6431      +/-   ##
==========================================
+ Coverage   66.33%   66.34%   +0.01%     
==========================================
  Files         183      183              
  Lines       23885    23885              
==========================================
+ Hits        15844    15847       +3     
+ Misses       6487     6478       -9     
- Partials     1554     1560       +6     

Flag	Coverage Δ
core-unittests	55.34% <ø> (+<0.01%)	⬆️
e2e-multicluster-test	31.25% <ø> (+0.08%)	⬆️
e2etests	33.09% <ø> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[FogDong]

Not sure if we need this, or should we discuss about the time of stale?

[wonderflow]

I don't think we need it for now, thanks for contributions!